Gravity furnace



y 4, 1946. '7 IVTR'. HIGLEY E'II'AL 7 2,400,352

.. GRAVITY FURNACE Filed Sept. 18, 1941 3 Sheets-Sheet 1,

- INVENTORS P76 :1 fl'en/vz E M64 E) I BY Pl/L/P M I/Wc Cor ATTORNEYS May 14, 1946. F. R. HIGLEY ETAL 2,400,352

I GRAVITY FURNACE Filed Sept. 18, 1941 s Sheets-Sheet s w I H" 1NVENTOR5 I ATTORNEYS top wall of the combustion chamber.

Patented May 14, 1946 UNITED STATE S PATENT:

OFFICE V GRAVITY FURNACE- Frank Higley, Cleveland Heights, andlPhilip W. McCoy, South Euclid,'0hio, assignors to The Bryant Heater Company, Cleveland, Ohio, a

corporation of Ohio Application September is, 194l, Serial No. 411,368 12 Claims. (Cl. 126-116) able for cleaning or replacementand for exposing the inner walls of the furnace for cleaning. Another object is the provision of a furnace of the type indicated comprising a series of metal rings superposed ne upon another of identical 1 size and form, having fins of graduated width with baiile plates arranged to concentrate the hot gases on the ring walls opposite'th maximum width of fins.

Other objects and features of novelty will appear as we proceed with the description of that embodiment of the invention which, for the purposes of the present application, we have illustrated in theaccompanying drawings, in which Fig. 1 is a vertical central sectionalview of a I gravity furnace embodying the invention.

Fig. 2 is an elevational view at right angles to Fig. l with the furnace casing and certain other parts broken awayin order to trate the invention.

Fig. 3 is a top plan view of the furnace, and Fig. 4 is a fragmental detail view of one of the rings on a larger scale. a

In the drawings, a generally rectangular outer casing is illustrated at I having a suitable base more clearly illusin form and size with ring i5l, may be fitted .over the latter ring. A third ring I53, also identical with ring l5l, fits over ring I52. Although three .of these rings are illustrated herein, a greater or lesser number may be employed, the number used being dependent upon the desired capacity of the furnace.

Each of the rings has a'series of integral external fins IT in vertical radialplanes and as'eries of integral internal fins l8 arranged preferably in the sameplanes with'fins ll. The fins of one.

ringare ofiset with respect to those of the rings above and below. Fins ll stopshort'of the upper and lower edges of the rings, their upper ends constituting stops which are useful in assembling the rings, that is in bringing them into alignment before they are pressed together. The fins of the inner and outer sets are widest where they meet thehorizontal plane indicated by the dotted line A in Fig. 4. s This plane corresponds with the parting plane established for the molding of the casting, and the fins have draft in respect to fin thickness as well as width, both starting from this plane. 1 The draft of the ring wall also starts from the same plane. However, we have adopted r a novel wall form because of the fact that'the I top half of the ringabove the parting plane has an external wall 19 which tapers'upwardly pro- II and having a large opening I! at the top through which warm air is distributed into a system of conductors, not shown, leading to the rooms to be heated.

In the lower part of the casing there is formed a combustion chamber l3 wherein is mounted the furnace burner, which may be of any desired type butis here illustrated as a gas burner l4. Surrounding a hole, in the top of. the. combustion overlapping portions of the ring walls must have a taper in orderto permit-the tight fit which we employ between the rings, while at the same time the draft must be kept at a minimum so as to hold down the weight of the casting.

In accordance with the present invention the viding a slope that is considerably greater than .the'necessary draft and aninternal wall with aslope which-provides the minimum necessary draft. On the lower half of the ring, on the contrary, the inside wall 2| is provided with the same slope or taper as the upper outer wall l9, while the outer lower wall 22 is almost parallel to the ringaxis, that is it has the minimum necessary chamber and extending upwardly therefrom is.a I

ring l5l of cast metal. This ring may be attached to the combustion chamber by any suitable means as by a series of fastening I 6, extending through holes drilled in the ring and registering holes in flanges struck up from the The upper, outer side wall of ring I5l is. tapered somewhat toward the top so that another ring I 52, identical.

draft and is parallel to wall 20.

of. ach ring which'is adapted'to fit onto the conical surface IQ of the upperhalf of the ring next below, these two conical surfaces havingthe same 1 slope'so that-whenthe rings are'pressed together an exceedingly tight fit results. a 7

As anintegral part of .the'castingwe form a hoop 23, located entirely in the upperhalf above the plane A, and spaced from theinner wall of the casting by the fins IS. The heat which the hoop absorbs may,- of course, be transferred Thus, there is provided a conical surface 2i on the lower half bolts r screws 3|.

ders 24 projecting inwardly beyond the hoop 23 which constitute supporting ledges for a horizontal baille plate 25. This plate is ordinarily not used with the lowermost ring l5l, but is used with all rings above the lowermost. Its function is to deflect the hot gases to the sides of the ring, where they must flow through the constricted annular passage between the wall of the casting and the hoop 23 in the zone where the fins l1 and H! are widest and thickest and therefore best adapted to transfer heat to the air outside the casting. These bai'ile plates fit loosely within the hoops 23.

Above the topmost ring we mount a header 26 with a bottom offset flange 21 which overlaps the upper edge of the ring I53 and is secured thereto by fastenings -16. The top of this header may be inclined as shown, and from its higher side wall a flue connection 28 extends through a suitable hole in the casing Ill. An opening 29 in the inclined top of the header is closed by a cover plate 30 which may be held in place by The opening 29 is of a size sufilcient to clear the battle plates 25. Hence, when the furnace needs cleaning, the cover plate 30 may be removed after which the uppermost plate 25 may be lifted off the shoulders 2| of the corresponding ring and withdrawn through the opening 29. Thereafter the plate or plates 25 below the uppermost one may be swing into vertical planes and lifted and removed one at a time. Thus, not only the plates 25 but also the inner surfaces of the rings as well as the fins II are exposed for cleaning, and are easily reached through the large opening 29. All of the joints between rings, between the lowermost ring and the combustion chamber and between the uppermost ring and the header may be sealed with furnace cement, not shown, so that no leakage of hot gases into the air stream is permitted. The fit between rings is, however, so tight that ordinarily no cement is needed in those joints.

Furthermore any leakage would be, away from the air stream rather than into it, so that no harm could result from small cracks or openmgs.

As illustrated, we provide a radiant heat guard consisting oftw'o semi-cylindrical sheets 32 that are flanged 'and' secured together at their vertical edges, the fastening means 33 serving also to draw these guard sheets into close engagement with the fins l1 upon which they are supported.

The whole structure may be braced by means of angle plates 34 between the casing and the cylindrical sheets 32.

In the operation of the furnace air enters the lower end of the casing outside of the combustion chamber l3 and flows upwardly around the perimeter of the rings l5ll53, both within and" without the radiant heat guard 32. The air thus becomes heated and is discharged into the room conductors from the opening in the upper end of the casing.

In accordance with the invention, the number of unlike parts necessary for the construction of furnaces of several different capacitiea'that is by utilizing different numbers of ring units, is unusually small, which, of course, has an important bearing upon the cost of construction.

Having thus described our invention, we claim:

1. In a furnace, a plurality of horizontal rings fitted together, outstanding fins on the out r surfaces of said rings, each fin being of maximum width near the central horizontal plane of the ring, a combustion chamber upon which the bottom ring is supported, horizontal bafile plates carried by certain of said rings near their central horizontal planes with clearance between the plates and rings for the passage of hot gases, and a conductor for air to be heated surrounding said rings. 1

2, In a furnace, a plurality of horizontal rings relatively thin at their top and bottom edges-and thick at the middle, the upper outer and the lower inner surfaces of said rings being sufiiciently conical to permit the rings to be fitted together, with each ring overlapping theone next beneath, outstanding fins on the outer surfaces of said rings, the upper ends of the fins terminating below the tops of the rings, each ring above the bottom one overlapping the one next beneath with its bottom edge just above the upper ends of the latters fins, a combustion chamber upon which the bottom ring rests, means carried by certain of the rings for directing hot gas flow through annular horzontal zones adjacent the ring walls, and a conductor for air to be heated surrounding saidrings.

3. In a furnace, a plurality of rings superposed one upon another and tightly joined together, internal fins on said rings, a concentric hoop integral with the fins of each ring and spaced thereby inwardly from the wall of the ring, a combustion chamber beneath the superposed rings, certain of the rings carrying horizontal bafile plates fitting within the hoops and serving with the hoops to force combustion gases into the annular spaces between the hoops and rings, and a conductor for air to be heated surroundng said rings.

4. In a furnace, a plurality of identical rings superposed one upon another, a combustion chamber beneath the rings, a fiue connection at the top of the rings, and a conductor for air to be heated surrounding the rings, each ring having a greatest thickness zone approximately midway of its vertical dimension and having anouter conical wall extending upwardly from said zone and an inner conical wall extending downwardly from said zone,.said conical walls having the same slope approximatelmwhereby the rings may be joined together with a close fit.

5. In apparatus of the class described, a cast ring having a parting plane perpendicular to its axis and intermediate its ends, internal and external fins arranged in radial planes through said axis, said ring and said fins having draft extending in opposite directions from said parting plane, and a ballle plate of smaller diameter than the internal diameter of the ring mounted concentrically in the ring substantially in said parting plane.- 1

, ring having a parting plane perpendicular to its "axis and intermediate its ends, internal and ex ternal fins arranged in the same radial planes through said axis, said ring and said fins having draft extending in opposite directions from said parting plane, and a baille plate mounted substantially in said parting plane and spaced from the ring walls by said internal fins.

7. In apparatus of the class described, a cast ring having a parting planeperpendicular to its axis and intermediate its ends, internal and'external fins arranged in radial planes through said axis, said ring and said fins having draft extending in opposite directions from said parting plane,

certain ofsaid internal fins having'inwardly extending shoulders directly beneath said parting plane, and a circular baiiie plate resting upon said shoulders.

8. In apparatus of the class described, a cast ring having a parting plane perpendicular to its axis and intermediate its ends interhaljaniexternalfins arrangedin radial planes through said axis, said ring and said fins having draft extending in opposite-directions from said parting plane,

a hoop cast integral with said internal fins spaced from the ring wall with its lower edge substantially invsaid parting plane,- and a circular b'ailie plate mounted within'the hoop also substantially in said plane. 1 r

9. In apparatus or the class described,v a cast ring having a parting plane perpendicular-to its ciently conical to permit joining, of the ring with other identical rings above and below by closefitting overlapping surfaces, the inner wall above said parting plane and the outer wall-below said plane having minimum draft.

11. In apparatus of the class described, a cast ring having a parting plane perpendicular to its axis and intermediate its ends, internal and external fins arranged in radial planes through said axis, the outer wall of the ring above said plane and the inner wall below said plane being sumciently conical to permit joining of the ring with other identical rings above and below by closefitting overlappingsurfaces, the outer-fins terminating short of the upper end of the ring and the'lnner fins terminating short of the lower end of the ring.

axis and intermediate its ends, internal and" ex-.-

ternal fins arranged in radial planes through said axis, the outer wall'of the ring above said plane and the inner wall below said plane being sufllciently conical to per'mitjoining of the ring with other identical rings above and below by closefitting overlapping surfaces,

10. In apparatus of the class described,a cast 5 ring having a parting plane perpendicular to its axis and intermediate its e'nds, internal and external fins arranged in radial planes through said axis, the outer wall of the ring above said plane and the inner wall below said plane being sufil FRANK R. HIGLEY. PHILIP W. MCCOY. 

